Conduit and method of making the same



May 14, 1935. R. A. sHlPLEY GONDUIT AND METHOD OF MAKING THE'SAME Filed June 2o, 1951 May 14, 1935. R. A. sHlPLEY A 2,601,316l

CONDUIT AND METHOD OF MAKING THE SAME Filed June 20, 193l v2 Sheets-ShearI 2 5 www "lllllllmw'll Patented May 14, 1935 y 2,001,316

UNITED STATES PATENT OFFICEv Roy A. Shipley, Pittsburgh, Pa., assigner to National Fireprooiing Corporation, Pittsburgh, Pa., a corporation of Pennsylvania Application June 20, 1931,`Serial No. 545,779

4 Claims. (Cl. 25-156) This invention relates broadly to conduit and vmentari Shape, and Showing Such Sections in to methods of making the same, and more particpositionv to be moved toward one another into ularly to conduit made up of sections having inintertting relationship to form a conduit; y terltting portions to assist in maintaining the Figure 3 is a longitudinal central vcross-sec- 5 integrity and alignment of the conduit. It retional view through a portionof a conduit length 5 lates still more particularly to the art of makshowing forming apparatus in position to shape ing conduit of material susceptible of ready an end of such length and after the shaping opworking or shaping, such, for example, as ceramic eration has been completed; material which in the green state may be cut, Figurev 4 is a perspective view of a forming Worked and shaped with little difficulty. tool, such as that of Figure 3, shown in'coope'r- 10 The invention further relates to conduit made ative relationship with an extremity of a conduit up of sections having one or more ducts adapted length for shaping such extremity, a portion of to be aligned upon disposal of the sections in the conduit length being cut away; cooperative relationship end to end Vand pro'- Figure is a perspective View of a forming vided with generally longitudinally directed comtool similar to that shown in Figure 4 but adapted `15 plementary projections and recesses extending for asomewhat diierent operation, a portion of generally peripherally of the ducts and adapted to the head ofthe tool being cut away for the sake interfit to assist in strengthening and maintainof clearness; l ing the integrity and alignment of the conduit; lFigure 6 is a View similar to Figure 3 showing and to a method of making such conduit seca forming tool, such as that of Figure 5,` in co- 20 tions, operative relationship with a conduit length;

I provide a conduit made up of sections com- Figure 7 is a fragmentary top plan view, with posed entirely of ceramic material, said conduit a portion cut away, of the' forming tool shown being of constant external and internal crossin Figure 5,' and 25 section, said sections having tapered intertting Figure 8 is a fragmentary perspective View of 25 peripheral projections and recesses at their ex one of the shaping devices. tremities. Y Referring now more particularly to the draw- I further provide a method of making conduit ings, Figure 1 shows in central longitudinal crosssections, comprising providing appropriate section a portion of a length 2 of extrudedceramlengthsy of material having ducts therethrough, ic material just as it comes from the. extrusion 30 and altering the shape of the ends of such lengths vdie and in the green or generally plastic state. to provide generally longitudinally extending pro- The length is of generally octagonal external jections and recesses adapted to interiit upon cross-section, as indicated in Figurel 4, and is alignment of such lengths to provide a conduit. provided centrally thereof with a longitudinally I also provide a method of making conduity secextending duct 3.

tions, comprising providing appropriate'lengths Inthe extrusion process. the green ceramic vof material having ducts therethrough adapted material is forced through la die and emerges vin to be aligned, and removing portions of the maa straight continuous length of substantially uniterial at the extremities of the ducts to provide form cross-section, such as the length shown in projections and recesses adapted to interi-lt upon Figure 1. l f l Y alignment of such lengths. The first step in the formation of conduit sec- Other Objects and advantages of the invention tions out ofthe extruded length comprises sev- `will become apparent as they following desoripering the1ength substantially perpendicmany to tion of a present preferred embodiment thereof its axis to provide pieces of desired lengths the 4;; Proceeds. end faces of which are substantially plane and 45 In the aCcOmpaIiYiIig dIaWiIigS I have ShOWn a parallel. Such` pieces at the time they aresev-y present preferred embodiment of the invention, ered from the extruded length are of'such cony wherein sistency that they may be handled without sub- Figure 1 is a longitudinal Central CrOSS-Sestantial damage thereto, but the green ceramic 56 tional view through a portion 0f a length 0f eX- material is readily workable and can be easily 5o truded ceramic material provided with a central cut and shaped. After cutting the extruded duct; length into the pieces mentioned, I preferably Figure 2 is a longitudinal central erOSS-SeG- shape the ends of the pieces by means of suittional view through portions of a pair of conduit able forming apparatus so as to produce generally l5,5 sections having adjacent extremities of complesimilar conduit sections the respective endsof 2 and the opposite extremity as shown at the right-hand side of such gure, although, if desired, both ends of a .sectioln'mayt be similarly shapediandsma'y cooperatexwithan endiof .an adjacent section shaped complementarily. The

conduit section extremity shown at the left-han'df side of Figure 2 is formed at the ..end.of ,a piece cut as above described from the extrudedlength by removing a generally ring-shaped mass of the green ceramic material fromztheinner portion4 of the end of the section; Similarly tliecond'uit section extremity shown at the right-handside of the same gure is formed at the end .of apiece cut as above described from the extruded length by removing a generally ring-shaped mass offthe zgreenceramic materialfromthe outer portion ofthe end of the section. Each of .the generally ring-'shapedmasses ofcerarnic material'which is removed is tapered, as clearly indicated in Figure andthe'respective ends are thusiormed of complementary. kshape and are adapted tor be 'nziovedgtogether into intertting relationship, the taper of the 'respective recesses and projections A.erialliing,easy and precise centering. As thefrespective'tapers'are at the same angle and the depth. of.. the recess in one extremity is substantially Aequal tothe length of the projection on the other, the two extremities whenpressed together form a conduit .whose internal and external cross-sections' are substantially constant 'in zspite of the joint.

" l Notonly does this provision assist in strengthening' the conduit, but it renders far-.simpler the assembly of. the sections than y. the prior method of. utilizingv dowel pins inl holes provided inthe extremities of the respective sections.

When the conduit is used `forcarrying .electric conductors the amount of` protection -and insulation afforded at the joints is precisely the same las .throughout the bodies ,of1 the sections and no enlarged vradially projecting portions are Ineces,- sary.l The. joints may, ifl desired, be cemented o rtapedfl l iQ'rhe, shaping of. the endsofthe sections may be performed either byhand or by machinery. For the salie-.of simplicity I have shownin/ the drawings a pairof hand tools, one for shaping oneivend of a preferred type of section andthe othe1 rfor. shaping the other end. Figures 3 vande is shown a tool for shaping .a.con duit sec- .tionextremity as-shown at the right-hand side .of Figure 2,-and in Figuresm, 6, kf7 and 8 is shown `a,.tool for .shaping a conduit sectionextremityas shown 4atthe left-hand side of Figure 2.

Referringnow more particularly to Figuresl and I4,5;the-ormingor shaping tool comprises a vificad.lifwliichY. is generally flatv and with.which is connected substantially` centrally thereof` and extending .fsubstantially Y perpendicularly thereafgen'erally cylindrical guiding portion 5 lhavingl'a smooth exteriorwadaptedto snugly t `within an extremity of a conduit duct whereby tovguidethe'tool for generally rotatable movement withrespect thereto. Connected with the .oppositeface of thehead is a handle 6 suitable Qi manualV operation for rotatingthe tool with 11espeCt-G 0 thefdut, l f 5:1111@ undervportion Vot the head 4 outside the guiding por=tion5 4substantiallyflat andsmooth the head... is provided .at .substantially equal intervals circumferentially thereof with notches or openings l, as shown in Figure 4. Connected with the head at each of such openings and extending generally downwardly and circumferentially therethrough is a shaping device 8. Such device isl made of strip metal bent in the manner shown and having a more or less sharp forward edge I f The ceramic material offwhich the conduit section is made is, as above mentioned, plastic and easily workable in the green state although it is compressed sufficiently to oier rm guiding resistance to the forming tool. The guiding portion 5 of the tool is preferably made so as to fit snugly but; nottightly within the duct in the conduit section in such manner that there is no substantial lateral play. The portion 5 is made long enoughso that it engages within the duct throughout a longitudinal distance sucient to prevent tilting of the tool. Furthermore, the guiding portion assists in supporting the green ceramicmaterial from within and preventing the duct wall from becoming deformed during the forming operation.

' The extremity of the guiding portion 5 -of the tool .is outwardly tapered, as shown at l0, to enlable the. tool to be easily inserted into the duct.

Onefof the cut portions of the extruded length of ceramic mate-rial is placed on end and the operator grasps `the tool by the handle 6 and inserts the guidingportion 5 downwardly into the duct until the lower extremities of the shaping devices 3 contact withvthe end wall of the extruded length... The operatorv then simultaneously turns they tool in the clockwise. direction and gently presses it downwardly substantially axially of the extruded length. vThe sharp forward edges 9.0i the vrespective shaping devices cut into the green ceramic material and sever portions. of the same from the end ofthe extruded length until the ilat bottom surface ofthe head il comes into contactwith the remaining portion of the end surface whereupon further movement of the tool axially of the extruded length is prevented. Slight further rotation ot the tool smooths off the cut surfaces and the end of the extruded length assumes the form shown at the right-hand side of Figure 2 and in Figures ,3 and 4. The tool is'thenwithdrawn from the duct, the partially formed conduitsection inverted andthe opposite end operated upon bythe same or a similar tool, preferablyby-a tool such as that shown in Figures 5, 6, 'lf and 8,l the-operation being substantially the samev asgthat above described except 4that an interior rather than-an exterior. portion ofthe `ceramic material at..the .end-oi. the 'extruded lengthiisfremoved so that the resultanteff'ect is as shownat the left-hand side of FigureZand in Figure 6; VDuring either or bothof theforming operations a core or` mandrel-like supporting member may be inserted into'the .opposite end of the extruded length to assist in maintaining and supporting it in proper position and preventing undesirable deformation thereof.

The tool shown in Figures 5, 6, l and 8A is similar to thatshown in Figures Sand .4 and correspondving reference v numerals. having., primes; axed The effect of the tool is to remove a generally annular portion interiorly of the end of the extruded length, as above mentioned, the outwardly projecting portion of the head 4' having a. flat under surface cooperating with the remaining portion of the end of the extruded length to prevent further movement of the tool longitudinally thereof.

The respective shaping devices 8 and 8 are formed to produce' the tapered projections at the extremities of the conduit sections, as above described, whereby the sections will properly intert and may be moved together into cooperative relationship without dimculty.

After the ends of the respective sections have been shaped, the sections are burned in the usual manner to produce nished conduit sections, as is usual in the art.

The former of the ends of the sections may be accomplished in various different ways, such, for example, as simply by a pressing and deforming operation which is possible on account of the plastic condition of the material, but I iindv it more satisfactory to use more or less pointed shaping devices which substantially cut into the material and shave oli ribbon-like elongated strips as the tool is rotated and moved longitudinally of the extruded length. Although I prefer to guide the tool internally of the conduit section by means of the duct wall, the tool may be guided otherwise, such, for example, as by the outer surface of the section, particularly when round sections are being made. v

The invention is equally applicable to vsingle duct and multi-duct conduit, the end of the section at each Aduct being formed in the manner explained. The invention is further applicable to curved or twisted sections, and in -fact the particular form of the section is immaterial, as will be appreciated. The terms conduit section and ,conduit length and similar expressions as used in the claims are not to be construed as being limited to conduit sections whose axesare straight of other In my eopending application Serin No. 545,780, l

led of even date herewith, kI have described and claimed the forming apparatus lwhich is described herein, and ltherefore no claim is -made herein specifically to such apparatus or tools. f WhileI have shown and described a-present preferred embodiment of the invention, it is td be" i y distinctly understood that the same is not lim` ited thereto, but may be otherwise variously vem bodied and practiced within the scope of the following claims. f i

I claim:

1. A method of making a ceramicconduit section, comprising providing a length of ceramic material in plastic state having a duct'therethrough, and inserting partially' into and bodily 1 turning with respect to said duct a unitarily operable lreaming tool having a portion `for removing part of the material of said length.4

` 2. A methodof making a ceramic conduit sec-`r tion, comprising providing a length of ceramic material in plastic` state having a duct therethrough', and simultaneously moving axially partially into said duct and bodily rotating with re- I spect to said length a reaming-tool having a portion` for removing par-t of the material vof said length.

3. A method of making a ceramic conduit sec-j tion, comprisingprovidingalength of ceramic` materialin plastic state having a duct therethrough, and simultaneously guiding by said ductand moving axially partially thereinto and bodily rotating with respect ,to said length a reamthe material of'said length.

4. A method of making a ceramic conduit section, comprising providing a length 'of ceramic material in plastic` state having a lduct therethrough and simultaneously guiding by said length of` material, moving axially thereof V`and' bodily rotating with respect thereto a tool hav- '4'5 ing a portion for removing part of the material of said length. m

ROY A. SHIPLEY. 

